In aerospace applications, it is common to use sandwich material, such as large honeycomb panels, and this material is often used as flooring, storage compartment doors, or internal was of aerospace vehicles. It is often necessary to provide an insert, such as one that is threaded to receive a screw to enable a hinge, bracket or other attachment. These inserts may be potted or mechanically installed in the sandwich material to allow for the fabrication of aircraft secondary structures, such as stow bins, galleys, and lavatories.
Traditionally, inserts are provided by drilling a cavity for the insert, locating the insert into the cavity, injecting a glue (which is likely a thermoset material) into the openings located onto the cap of the insert to fill the cavity drilled, leaving panels enough time to allow the curing of the adhesive (24 hours or more) and removing the cap. Such thermoset adhesives also require significant cure time of up to 24 hours or more. Therefore, space or storage areas for these large panels is needed to allow the adhesive to cure during this time period. Other disadvantages for some thermoset adhesives include a limited shelf life or specific storage condition requirements (e.g., must be stored at cooled temperatures) or handling precautions, or require accurate mixture of 2 components.
Based upon the foregoing, there is a need for an adhesive that avoids these common problems encountered with a thermoset adhesive, such as an adhesive that is clean and fast adhering and hardening.